Answer:
Federalism as a form of governance continues to be challenged and tested in many federal countries, not only in the United States. In particular, <em>environmental and immigration issues</em> can be expected to become only more salient in the next decade.
While the <u>federal government</u> is often entrusted with addressing environmental issues and complying with the international standards, it is the task of state and local governments to carry out regulations implementation in the field. <u>State governments</u> need to identify the most optimal ways to deal with particular environmental issues, like sire contamination, and request federal support ahead of time.
Immigration, on the other hand, can be an important subject to citizens all over the country and matter of <u>federal government</u> major decision making, but it is the bordering states that have to deal with its actual impact. <u>State governments</u> need to foresee immigration waves and adverse effects of tightening immigration laws. For example, the fact that many illegal immigrants would choose to settle in a state permanently without risking crossing the border.